Improvement in burglar-alarms



J. H. THORP. Burglar Alarm.

No. 109,970. Patented Dec. 6, 1870.

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JAMES HARRY radar, orNEW YORK, N. Y.

Letters Patent No. 109,970, dated December 6, 1870. I

IMPROVEMENT IN BURGLAR-ALARMS;

The Schedule referred to in these Letters Patent and making part 01 the same.

To all whom. it may concern Be it known that I, JAMES HARRY Tuonr, of New York City, in the county of New York, and in the State of New York, have invented certain new and useful Improvements in Burglar-Alarm; and do hereby declare that the following is a full,.clear, and exact description thereof, reference being had to the accompanying drawing and-ito the letters of reference marked thereon making a part of this specification.

The nature of my invention consists in the construction and arrangement of the mechanism for op- -crating a burglar-alarm, as will be hereinafter fully In order to enable'ot-hcrs skilled in the art to which my invention ap'pertains to make and use the same, I will now proceed to describe its construction and operation, referring to the annexed drawing, in which- Figure 1 isan inside view of a door with'burglaralarm.

r Figures 2 and 3 are detached views of the mechanism by which the alarm is operated. A represents a door-frame; and B, the door. On the door B is fastened the bolt 0, which looks into the keeper D, attached to the door-frame.

The shape of the keeper D is the same as those generally used for that purpose, having flat flanges or ends.through which screws pass to attachit to the door, while the centeris bulged outward. In this case,

however, the bulge is largerthan what is necessary for the reception of the end of the bolt.

The bulge of the keeper D is slotted crosswise,and in this slot is inserted the sliding plate a, which fits in grooves extending inward on the inside of said bulge from the endsof the slot.

Theedges of the sliding plate a are grooved, and in the same is placed a wire, b, which passes under the ends or fiat flanges of the keeper, which are grooved for that purpose on the inner side.

One end of the wire I) is fastened to the d'ooi frame,

while the other end is connected with the lever of a clock-alarm, E, placed at any point desired.

The inner end of the sliding plate ahas a hole through which the bolt 0 passes when locked. It'the door is pushed inward without first withdrawing the bolt, the bolt will force the sliding plate outward ti'om the keeper, and consequently start the alarm E.

Having thus fully described my inyention,

What I claim as new, and desire to secure by Letters Patent, is g Y The keeper D, slotted and grooved as described, in combination with the grooved sliding plate a and wire I), said wire connecting with a burglar-alarm, substanti ally as and for the purposes herein set forth.

In testimony that I claim the foregoing, I have hereunto set my hand this 15th day of October, 1870.

- JAMES HARRY THORP.

Witnesses:

E. VAN TASSEL, GEORGE Bosnnn. 

